In a conventional pneumatic tire, a plurality of sipes extending in the tire width direction are formed in blocks (land portions) on the tread, and the sipes extend while bending in the depth direction thereof (see JP 2013-189131 A (PTL 1)).
In sipes that have such a bent portion, the block 's opposing wall surfaces that form the bent portion contact each other and interlock when the block deforms in the tire contact patch. This interlocking effect has been recognized to improve the rigidity of the block and the grounding property of the tire surface (tread surface).
One reason for improving the block rigidity and the grounding property of the tire surface is to improve the motion performance of the tire on snowy and icy roads, but numerous sipes could also be provided for the purpose of guaranteeing the biting and digging-up effect at the sipe edge. In order to suppress excessive block deformation as a result of the numerous sipes, a variety of shapes have been proposed for sipes.
The interlocking effect by the opposing wall surfaces of the block is also expected to contribute to improving the motion performance of the tire on road surfaces other than snowy and icy roads.